20642404123 has 4 divisors (see below), whose sum is σ = 22518986328. Its totient is φ = 18765821920.

The previous prime is 20642404103. The next prime is 20642404141. The reversal of 20642404123 is 32140424602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20642404123 - 2⁵ = 20642404091 is a prime.

It is a super-2 number, since 2×20642404123² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20642404091 and 20642404100.

It is not an unprimeable number, because it can be changed into a prime (20642404103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 938291086 + ... + 938291107.

It is an arithmetic number, because the mean of its divisors is an integer number (5629746582).

Almost surely, 2^20642404123 is an apocalyptic number.

20642404123 is a deficient number, since it is larger than the sum of its proper divisors (1876582205).

20642404123 is a wasteful number, since it uses less digits than its factorization.

20642404123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1876582204.

The product of its (nonzero) digits is 9216, while the sum is 28.

Adding to 20642404123 its reverse (32140424602), we get a palindrome (52782828725).

The spelling of 20642404123 in words is "twenty billion, six hundred forty-two million, four hundred four thousand, one hundred twenty-three".